|Publication number||US7004559 B2|
|Application number||US 10/728,859|
|Publication date||Feb 28, 2006|
|Filing date||Dec 8, 2003|
|Priority date||Dec 8, 2003|
|Also published as||US20050122371, WO2005053959A2, WO2005053959A3|
|Publication number||10728859, 728859, US 7004559 B2, US 7004559B2, US-B2-7004559, US7004559 B2, US7004559B2|
|Original Assignee||Scitex Vision Ltd.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (6), Referenced by (2), Classifications (7), Legal Events (7)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present invention generally relates to cleaning and maintenance stations for inkjet print head nozzle plate cleaning an maintenance and to method of cleaning and maintenance of ink jet print head nozzle plate. In particular the invention relates to non-contact method of cleaning and maintenance of inkjet print head nozzle plate.
Inkjet printing has gained popularity in a number of applications. One of the growing printing applications is printing of billboards, banners and point of sale displays. The ink-jet printing process involves manipulation of drops of ink ejected from an orifice or a number of orifices of a print head onto an adjacent print medium or substrate. An ink-jet print head consists of an array or a matrix of ink channels or cavities each ending by an orifice or nozzle. The nozzles of an array or a matrix of ink channels are typically made on a common substrate called nozzle or orifice plate. Usually, one of nozzle plate surfaces is attached to an array or a matrix of ink channels in a way that each nozzle faces a corresponding ink channel. The other surface “open” surface faces the printed media or substrate. Each nozzle selectively ejects ink droplets in the direction of the printing substrate. A given nozzle of the print head ejects the ink droplet in a predefined print position on the media. An assembly of the adjacently positioned on the media ink droplets creates a predetermined print pattern or image. Relative movement between the media or substrate and the print head enables printing substrate coverage and image creation. The selection of printing media is large and varies from paper and fabric to metal and glass.
The quality of the print produced by an ink jet printer to a large extent depends on the state of the nozzle plate and especially the surface of the nozzle plate. Dry and free of debris nozzle plate surface enables accurate droplet placement reducing droplet position caused printing artifacts. It is however, difficult to maintain the nozzle plate surface dry and free of debris. Ink mist formed during droplet ejection process resides on the nozzle plate surface; dust, paper and fabric lint remain on the nozzle plate surface. When printing is performed with UV curable ink, ink mist and residue might be cured by stray light on the nozzle plate surface. Although different coatings to reduce nozzle plate surface wetting and static attraction have been developed only repetitive and frequent nozzle plate surface cleaning helps to maintain correct operating status of the nozzle plate.
There is a number of techniques developed for cleaning of the “open” or facing the printed media nozzle plate surface. Some of these techniques relay on a simple wiping process, where a soft blade, such as one made of fluoro-silicone wipes the nozzle plate surface periodically. This operation wipes out debris and excess ink from the nozzle plate surface returning it to the original dry and free of debris state. The drawback of this technique is that debris and excess ink can contaminate some of the nozzles during the wiping step. Moreover residual ink located on the soft blade may contaminate the nozzle plate surface and therefore lead to a result opposite to what was expected.
The soft blade wiping method is not applicable to print heads operating with UV curable ink. Often UV curable ink residue always present on the soft blade cures or is in process of curing becoming a hard body. Wiping nozzle plate surface with a blade having on it cured ink particles not only scratches the nozzle plate surface, it contaminates the nozzle plate and clogs the nozzles making the print head unusable.
Another method of wiping is by a cloth wetted in a cleaning solution. The cloth is rolled from a roller-to-roller and thus avoids nozzle plate surface contamination, however lint and hard particles that are present in the debris may scratch the nozzle plate surface and damage the anti-wetting coating.
Methods of non-contact cleaning by a stream of fluid are also known in the art. U.S. Pat. No. 4,970,535 to Oswald et al., discloses an ink jet print head face cleaner that provides a controlled air passageway through an enclosure formed against the print face. Air is directed through an inlet into a cavity in a body. The body has a face with an opening into the cavity. This face is sealingly placeable against the print face. The cavity has a limited size so that air is directed without interruption through the cavity past the ink jet apertures, and out an outlet. The cleaner body is coupled resiliently to a platform to allow positioning of the body and print faces flush with each other. A vacuum source is preferably attached to the outlet to create a sub-atmospheric pressure in the cavity to further seal the two faces together. A collection chamber and removable drawer are positioned below the outlet to facilitate disposing of removed ink.
The fluid stream is oriented along the nozzle plate and moves ink residue from one end to another. There always exist a possibility that some residue will be trapped in a nozzle and clog it. Use of vacuum and sealed compartment increases the cost of the solution.
U.S. Pat. No. 6,196,657 to Hawkins et al. discloses a multi-fluidic cleaning for an ink jet print head and a method for assembling the same. The print head has a surface defining at least one orifice there through the at least one orifice being susceptible to being obstructed by contaminants. A cleaning assembly of the invention is disposed proximate the surface for directing a flow of fluid along the surface and across the at least one orifice to clean contaminants from the surface and the at least one orifice. The cleaning assembly includes a cup sealingly surrounding the at least one orifice, the cup defining a cavity therein. The cleaning assembly further includes a valve system in fluid communication with the cavity for allowing a fluid flow stream consisting of alternating segments of at least one liquid cleaning agent from a liquid cleaning agent source and another element such as a gas from a gas source or a second liquid cleaning agent from a liquid cleaning agent source into the cavity.
Hawking also requires creation of a sealed compartment that increases the cost of the solution. The fluid stream is oriented along the nozzle plate and moves ink residue from one end to another. There always exist a possibility that some residue will be trapped in a nozzle and clog it.
U.S. Pat. No. 5,184,147 to MacLane et al discloses an ink jet print head cleaning and maintenance system that has a purge chamber for applying a vacuum to a nozzle orifice surface. A specialized baffle diverts ink entering the purge chamber away a vent port through which the vacuum is drawn. An elongated wipe engages and wipes the orifice surface and is preferably moved at an extremely slow rate across the surface to enhance the wiping operation. An air knife directs a narrow stream of air across a portion of the nozzle orifice surface with air from the air stream being scanned across the surface for cleaning purposes. A specialized drip edge is positioned beneath the orifice surface for directing drops of ink away from the ink jet print head, the drops of ink being generated during the cleaning procedures. A mechanically simple cam mechanism coupled to a rotatable drum of the printer may be used to shift the maintenance system against the nozzle orifice surface for cleaning purposes.
The system however, requires a special mechanism for scanning the air stream across the surface for cleaning purposes. The cleaning system itself requires a positioning mechanism, although a simple one, to be employed for placing in a working position and returning to a idle state.
U.S. Pat. No. 6,497,472 to Sharma et al. teaches a print head that comprises a print head body defining an interior chamber and an orifice plate. The orifice plate has an outer surface and further defines a cleaning fluid orifice through the orifice plate for conducting a flow of a cleaning fluid through the cleaning fluid orifice and onto an outer surface of said orifice plate. The orifice plate also defines a drain orifice for conducting a flow of cleaning fluid from the surface to the interior chamber. A supply of pressurized cleaning fluid is disposed in said cavity and connected to the cleaning fluid passageway. During cleaning operations, the fluid flow system defines a flow of a cleaning fluid from the passageway and onto said outer surface. The drain orifice receives cleaning fluid from the outer surface and channels the cleaning fluid into the fluid return.
Sharma discloses that all print head facilities are part of the print head and accordingly the cost of the print head is increased. Special sealed compartment through which the cleaning solution flows is temporarily created for the cleaning process.
Therefore, there is a need in the industry in for a method of non-contact, ink jet print head nozzle plate surface cleaning solution. A solution that would provide nozzle plate cleaning without mechanical contact between the nozzle plate and the cleaning tool and would not require manual interference.
All of the above mentioned print head cleaning methods and devices are adapted to clean only one print head at a time. Most of the present ink jet printing system is printing with a block of print heads, where a number of print heads print the same color. This enables the printers of getting a higher throughput and high printed image density. The prior art solutions do not suggest a method of non-contact or contact simultaneous (parallel) cleaning of all print heads.
There is also a need in the industry for a cleaning solution that would not contaminated by the cleaning fluid stream the ink ejecting nozzles.
There is a further need in a cleaning solution that would not require special sealed compartments or vacuum for residue removal. A cleaning solution that could be easy portable from one print head shape to a print head having a different shape of width or array length.
It is therefore an object of the present invention to provide a method of non-contact, ink jet print head nozzle plate surface cleaning solution. A solution that would provide nozzle plate surface cleaning without mechanical contact between the nozzle plate and the cleaning tool and would not require manual interference.
It is an additional object of the present invention to provide a method of non-contact ink jet print head nozzle plate surface cleaning solution that enables simultaneous (parallel) cleaning of a large number of print heads.
It is a further object of the present invention to provide a non-contact ink jet print head nozzle plate surface cleaning solution, where the flow of the cleaning fluid that would not contaminate the ink ejecting nozzles.
It is still an additional object of the present invention to provide a non-contact ink jet print head nozzle plate surface cleaning solution that would not require special sealed compartments or vacuum for residue removal. A cleaning solution that could be easy portable from one print head shape to a print head having a different shape of width or array length.
These and other objects of the invention could be achieved by a non-contact ink jet print head nozzle plate surface cleaning method, comprising steps of:
There is also provided according to the teachings of the present invention, a non-contact ink jet print head nozzle plate surface cleaning method wherein said scanning open surface movement is part of a regular scanning pass or part of a scheduled scanning pass. The frequency of the scheduled scanning pass depends on the nozzle plate surface conditions and printed results.
There is also provided according to the teachings of the present invention, a method of non-contact ink jet print head cleaning with an air flow stream wherein the length of said air exit slit is equal or larger than said nozzle plate surface major dimension and parallel to said air exit slit or the largest dimension of a two-dimensional (matrix) nozzle array.
There is also provided according to the teachings of the present invention, a method of non-contact ink jet print head cleaning wherein each section of said pressurized air stream cleans only one appropriate nozzle of a nozzle array and where the angle at which pressurized air stream is hitting said nozzle plate surface is less than 90 degrees.
There is also provided according to the teachings of the present invention, a method of non-contact ink jet print head cleaning wherein ink and debris collecting means are disposable means such as sponge, cloth and similar. Alternatively, ink and debris collecting means may be connected to a drain.
There is also provided according to the teachings of the present invention, a non-contact ink jet print head nozzle plate surface cleaning method, comprising steps of:
The invention is herein described, by way of non-limiting example only, with reference to the accompanying drawings, wherein:
The principles and execution of a method according to the present invention, and the operation and properties of an ink jet print head cleaning and maintenance device operating in accordance with the method of the present invention may be understood with reference to the drawings and the accompanying description of non-limiting, exemplary embodiments.
In accordance with the present invention the non-contact ink jet print head nozzle plate surface cleaning method is performed as follows: when the amount of ink residuals and debris 26 accumulated on nozzle plate surface 24 adversely affects the printing process arrangement 28 moves in the directions indicated by arrows 38 and 40 until print head 20 is positioned over arrangement 28. A supply of pressurized air stream begins. Pressurized air stream exceeds through the slit in sidewall 30 in form of an air knife or curtain 52. The length of air curtain 52 is at least equal or larger than the major dimension M of nozzle plate surface 24. Air curtain 52 hits at an angle surface of nozzle plate surface 24 on which ink residuals and debris 26 are accumulated. Forces created by air curtain 52 remove ink residuals and debris 26 from the surface of nozzle plate 24. Scanning movement of arrangement 28 in direction of arrow 40 might be actuated for better removal of ink residuals and debris 26. Since the length of air curtain 52 is at least equal or larger than the major dimension M of nozzle plate surface 24 air curtain 52 cleans all of the nozzles simultaneously.
Forces created by air curtain 52 remove ink residuals and debris 26 from the surface of nozzle plate 24. Sidewall 34 that generally extends over the level set by nozzle plate surface 24 prevents spreading of removed ink residuals and debris. Removed ink residuals and debris hit sidewall 34 and flow to ink and debris collecting means 46 such as sponge or similar fluid absorbing material placed on the bottom of arrangement 28. When ink and debris collecting means 46 collect certain amount of ink they may be exchanged on fresh material and disposed. Alternatively sidewall 34 may be coated by ink and debris collecting means, such as foam or all of the arrangement 28 may be made disposable. In addition to this and in order to ensure longer operation of the printer the bottom of arrangement 28 with the help of tubing 50 is in fluid communication with a drain.
For better nozzle plate surface cleaning the air stream provided by air curtain 52 should be tangential to nozzle plate surface to be cleaned. This however, may be complicate to implement and an angle between the air stream and the nozzle plate surface will exist. The angle would be less than 90 degrees when measured between a perpendicular to the nozzle plate surface and the direction at which pressurized air stream is hitting nozzle plate surface is less than 90 degrees.
Using this method a true non-contact cleaning of the surface of the nozzle plate is accomplished in few seconds. Proper cleaning depends on the relation between such system parameters as width of linear air exit opening, air curtain to nozzle plate surface angle and time duration of the process. In the particular setting tested the distance between the surface of nozzle plate 24, and air exit slit 32 through which pressurized air from air conducting channel 44 exits was between 1 mm to 15 mm and preferably 12 mm to 8 mm, the pressure of the air stream was 0.15 to 0.5 atmosphere and preferably 0.2 to 0.3 atmosphere. The width of air exit slit 32 was 0.05 mm to 0.3 mm and preferably 0.1 mm. The speed of the relative movement between the surface of nozzle plate 24, and air curtain (stream) was 15 mm/sec to 50 mm/sec.
Although XAAR XJ 500/360 print head having a 500 nozzles linear array was used as an example, the cleaning method is equally applicable to ink jet print head having a two-dimensional nozzle array such as MAGICŪ print head, commercially available from Scitex Vision, Netanya, Israel. In each case, the nozzle arrays substantially span the major dimension of the nozzle plate, but leave relatively small attachment regions and/or inactive regions near the extremities as is generally accepted in the art.
The cleaning method has been described as a process that is performed only when a need arises. For the purpose of preventive maintenance the non-contact print head nozzle plate surface cleaning may be performed at the beginning or end of each printing cycle or even more frequent at the end or beginning of each scanning pass. Periodical cleaning not related to any specific cycle is also possible, although it reduces the machine throughput.
Ink jet print heads usually require continuous cleaning or maintenance. Since print heads do not operate continuously, maintenance may be scheduled for the end of printing cycle when the print head becomes idle. Prior art cleaning or maintenance stations require print head block movement to and from the maintenance area, where the maintenance area is typically implemented as a static portion of the substrate support surface or an additional portion of the machine. This movement requires some time and results in reduced printing duty cycle. The present invention reduces this time and increases the useful printing duty cycle.
Ink jet printer having a maintenance station 116 traveling with print head block 114 has the advantage of having higher printing duty cycle, since there is no need to move print head block 114 to a specific location for print head cleaning. Cleaning might become a part of each scanning pass or a number of scanning passes as required by the print head nozzle plate conditions and printing results.
For cleaning print head block 114 as part of scanning pass moves and positions over maintenance station 116. Airflow is activated and print head block 114 continues its movement in the direction indicated by arrow 120. Airflow 52 (
In addition to air flow-cleaning arrangements 92 cleaning and maintenance station 116 has vacuum suction nozzles 130 mounted on mounts 134 and connected to a source of vacuum. When air flow-cleaning arrangements 92 is operative to clean a nozzle plate surface having a relatively large amount of ink residuals and debris to be removed, for example after print head purging, excessive ink may reach and reside on the edges of soft fluoro-silicone sidewall 34 (
The nozzles of ink jet print heads when idle should be closed to prevent nozzle clogging and ink drying on the nozzle plate surface. This operation is called capping. Capping stations are also implemented as a static portion of the substrate support surface or an additional portion of the machine. Capping commences at the end of each printing cycle when the print head becomes idle. This requires however to move and position the print head block over the capping station.
In accordance with the present invention capping station may be implemented as an arrangement traveling with print head block 114.
Both the capping and the cleaning and maintenance station may be implemented as two separate modules. When one of the modules is operative it blocks access to the other module. One of the modules may be an airflow-cleaning module where the other module may provide the orifice plate capping function.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US4591873 *||Apr 12, 1985||May 27, 1986||Eastman Kodak Company||Ink jet printing apparatus with orifice array cleaning system|
|US4970535||Nov 27, 1989||Nov 13, 1990||Tektronix, Inc.||Ink jet print head face cleaner|
|US5184147||Apr 22, 1991||Feb 2, 1993||Tektronix, Inc.||Ink jet print head maintenance system|
|US5493319||Apr 5, 1994||Feb 20, 1996||Canon Kabushiki Kaisha||Method of restoring ink ejection by heating an jet head before cleaning|
|US6196657||Jun 16, 1999||Mar 6, 2001||Eastman Kodak Company||Multi-fluidic cleaning for ink jet print heads|
|US6497472||Dec 29, 2000||Dec 24, 2002||Eastman Kodak Company||Self-cleaning ink jet printer and print head with cleaning fluid flow system|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US8376507||Mar 10, 2011||Feb 19, 2013||Hewlett-Packard Development Company, L.P.||Non-contact inkjet print head cleaning|
|US9358791||Feb 12, 2015||Jun 7, 2016||Hewlett-Packard Industrial Printing Ltd||Printhead nozzle maintenance|
|International Classification||B41J2/165, B41J|
|Cooperative Classification||B41J2/16552, B41J2/16517|
|European Classification||B41J2/165C3, B41J2/165C|
|Dec 8, 2003||AS||Assignment|
Owner name: SCITEX VISION INTERNATIONAL LTD., ISRAEL
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ALIAGA, CHRISTOPHE;REEL/FRAME:014791/0758
Effective date: 20031202
|Jan 5, 2004||AS||Assignment|
Owner name: APRION DIGITAL LTD., ISRAEL
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SCITEX VISION INTERNATIONAL LTD.;REEL/FRAME:014853/0069
Effective date: 20031229
|Nov 2, 2004||AS||Assignment|
Owner name: SCITEX VISION LTD., ISRAEL
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ARION DIGITAL PRINTING, LTD.;REEL/FRAME:015945/0698
Effective date: 20041031
|Feb 14, 2006||AS||Assignment|
Owner name: HEWLETT PACKARD INDUSTRIAL PRINTING LTD., ISRAEL
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SCITEX VISION LTD.;REEL/FRAME:017163/0608
Effective date: 20051101
|Oct 5, 2009||REMI||Maintenance fee reminder mailed|
|Feb 28, 2010||LAPS||Lapse for failure to pay maintenance fees|
|Apr 20, 2010||FP||Expired due to failure to pay maintenance fee|
Effective date: 20100228